Thank you, Paulie. Good morning, everyone, and thanks for taking the time to join us on the call this morning. I am joined on the call by Deputy CEO, Paul Criddle, CDO, Shane Clark, and CFO, Will Nguyen. You will have seen that we released three significant updates to the ASX today. These announcements are the culmination of a significant amount of work and progress at both our projects and mark a very important inflection point in where Capricorn is headed in the next five years. I think we are on the cusp of a very exciting time for the company. Firstly, today, we updated reserves at both Karlawinda and Mount Gibson. These updates increase Capricorn's gold reserves to 5.2 million ounces. The reserves underpin long mine lives at both projects.
With both projects located in WA and being low cost with low technical and operational complexity, this puts Capricorn in a fantastic position to deliver value to shareholders over the long term. The second announcement we made today was an update to the Mount Gibson Pre-Feasibility Study. This study is our first opportunity to bring the exciting underground mine at Mount Gibson into the production profile. We have a development plan that allows the underground mine to commence contemporaneously with the open pit operation, allowing forecast gold productions to ramp up to 260,000 ounces per annum within two and a half years of the start of the project.
With our strong balance sheet and cash flow from Karlawinda, Capricorn expects to be able to fund the development of the project internally and the low operating cost of the project, we believe will see Mount Gibson become one of the standout gold mines owned in the Australian mid-tier industry. The third announcement we made this morning refers to our Range 500 project. This reflects Capricorn's aspiration to take the current 400,000 ounce per annum gold production outlook to beyond 500,000 ounces within the next five years. This project articulates our belief that in the medium term, the underground inventory at Mount Gibson will continue to grow.
We see the potential that we will reach a tipping point where we will have more underground inventory than we can process annually through the Mount Gibson mill without constraining the open pit contract beyond disruption point. This brings into focus the 1.38 million ounces of resources, tenure, and processing site at Golden Range, located 60-100 kilometers north of Mount Gibson that we acquired through scheme of arrangement with Warriedar Resources last year. Our thinking is that in the fullness of time, it may well make a lot more sense to truck overflow high-grade Mount Gibson underground ore north to Golden Range rather than trucking lower grade Golden Range open pit ore south to Mount Gibson.
Particularly given that lower grade Golden Range material would only warrant getting milled at Mount Gibson at the end of the Mount Gibson mine life. The rationale for trucking overflow high-grade north could lead us to build a second processing hub at Golden Range to process high-grade along with open pit ore from Golden Range. Obviously, this strategy is built on understanding the extent of underground resources at Mount Gibson that will underpin it. We're very conscious that it takes time to drill underground resources into resource categories sufficient for production forecasts. With this in mind, Range 500 reflects the board's confidence to commit time and money to evaluating the non-resource aspects of a second pro cess hub at Golden Range in parallel with underground drilling.
This study will consider plant size, infrastructure requirements, capital cost, and the permitting requirements for a second processing hub. This study will run parallel with aggressive drill outs of underground resources at Mount Gibson and open pit resources at Golden Range. The target is for these work streams to coalesce to a PFS and FID in calendar year 2027. I advise listeners of the following important qualification. It must be noted that the Range 500 project is an aspirational goal and not yet a production target or forecast. The company does not yet have reasonable grounds to believe the aspiration can be achieved.
Having said that, I can say that I'm really excited about the potential for growing and processing underground resources at Mount Gibson and how this might allow us to optimize not just production levels and mine life , but also the value of the broader Mount Gibson project, including Golden Range in the medium term. We understand the work that needs to be done, and we understand that that needs to be successful for us to achieve Range 500. Having said that, we really look forward to delivering the results of those work streams over the next 12 months. I'll now hand over to Paul and Shane for more detail on some of the key points from today's announcements, and then we'll wrap it up and take any questions that you might have.
Thank you, Mark. 33% growth in global reserves to 5.2 million ounces is a fantastic outcome and a product of strong continuity and geometry at depth at Karlawinda and the rapidly developing opportunity at Mount Gibson, along with robust and well-tested in-house estimation practices. Delivering an inventory of real scale and quality, now highlighting the emerging underground contribution to reserves and increasing production profile. With 10 and 19-year mine lives at the two projects and a 400,000 ounce per annum production outlook, Capricorn is a standout for scale and longevity in the mid-tier space. At Karlawinda, we've delivered our standard biennial extension of resource drilling and therefore reserve conversion, down dip along our extremely predictable river deposit. Yes, there's been a modest cost increase in the resultant reserve shell at AUD 2,600.
However, this is the sensible cost of keeping the mine life at over a decade after five years of operation and a major throughput in production expansion. That said, in the current gold price environment, there are historic opportunities at the project like K3 and Francopan, currently undercover, that begin to make sense at these prices and will be pursued with rigor in the coming years.
All right. Thanks, Paul. This update to the Mount Gibson reserve is highlighted by the maiden underground ore reserve, lifting the inventory to an impressive 3.7 million ounces. 12 months ago, we released the maiden underground resource estimate, followed by a trade-off study that defined the cost inflection point between the Orion South open pit and underground projects. Delivering 1 million ounces of reserve growth in that timeframe is extremely pleasing. That nearly two-thirds of that uplift has come from drilling within unchanged conservative AUD 2,200 per ounce shell assumptions is exceptional. We now have a fully optimized open pit position that underpins an exciting underground growth plan. We believe we've now validated the economics of underground operations at Mount Gibson, having taken the first target from discovery through to full project feasibility rigor.
Further increases in the production profile and future inventories will surely follow, and we'll discuss the associated targets in more detail later. Notably, once in production, Mount Gibson's 3.7 million ounce reserve will rank as the third largest gold-only reserve base amongst Australian ASX-listed assets and at a lower gold price assumption. For the Mount Gibson PFS, it has delivered. The combination of the initial open pit and plant development, together with the inclusion of underground reserves for the first time, underpins an impressive production rate of 260,000 ounces per annum by year three and a 19-year mine life. This delivers 3.5 million ounces of production and generates AUD 12 billion in pre-tax free cash flow.
A modest capital outlay of AUD 474 million is paid back in just 14 months, supported by an industry-leading all-in sustaining cost of AUD 1,870 per ounce, driving exceptional returns. Subject to permitting, we are targeting commencement of development in Q2 FY27, followed by a 15-month post-access period of pre-production mining and construction. The underground construction program will run contemporaneously with the initial construction phase, with the first development gold produced in the second year of operations and full production rates achieved in year three. The additional drilling completed whilst advancing permitting has clearly underpinned a materially larger and stronger project. Mount Gibson is a straightforward operation that has been scaled and scheduled to deliver consistent productivity at an industry-leading cost base.
With eight kilometers of strike across open pits, the project offers substantial scheduling flexibility, enabling us to maintain a relatively consistent stripping ratio of 5 to 1 over the life of mine. The underground component contributes in a similarly efficient manner. Its long, continuous strike length supports up to 1.5 million tonnes of annual production, requiring only the development of several levels a year to achieve this. The clear opportunity now lies in expanding the underground inventory and with it, the steady state production levels. We hold strong confidence in this pathway, underpinned by the reliable conversion rates demonstrated in the recent drilling programs. I'll now hand back to Paul.
Thanks, mate. As mentioned earlier, we believe we have taken the time afforded us during permitting to deliver a facility that respects the longer mine life and now also treats the underground ores. For a modest increase in pre-production capital, we are now delivering a substantially different project, inclusive of underground mine establishment, development, a more robust comminution circuit, and total flow sheet that processes a much longer mine life with multiple feed streams. Said, the processing infrastructure that we will build is familiar to us. The 5 million tonnes per annum tertiary crush ball mill and CIL flow sheet is very similar to that of our previous and currently operated projects. Our design approach is expected to deliver inbuilt latency, resulting in Karlawinda-esque performance relative to nameplate.
This metallurgical rigor that is inherent in our design and construction process is what delivers the industry-leading processing costs that you see in the PFS. With this in mind, I'd encourage you to comp our capital intensity as a function of annual tonnes milled or ounces produced. With that, I believe we're extremely well-positioned relative to recent projects of similar scale. Although the underground reserve from Orion South is our first as Capricorn, the development approach is very similar. The defining characteristic of the Orion South underground project is its technical simplicity, driven by long strike lengths, favorable ground conditions, and consistent geometry that drive excellent productivities and low operating costs.
The feature driving this is the 1,600-meter strike length, delivering an average of 4,000 ounces per vertical meter or 100,000 ounces per stoping level in the upper 3 levels of the mine. We have not designed nor want to operate a complex mine. The ore body allows this. Through the main section of the deposit, the average width of the loads is 5 to 10 meters, the ground competent, and the deposit dip angle of 70 degrees is quite consistent, lending itself to low dilution, productive long-hole open-stoping mining. Further, the productivities assumed here are sensible, especially when looked at in the context of the consistency of the geometry noted above, again, driving low-cost mining. The uplift in grade and production profile due to the Orion South underground's contribution is material.
The underground inventory delivered at Orion South is in its infancy and the extension of this system and others like Lexington shown here, adjacent to the Orion South underground mine, will likely only see a continuation of there being an excess of mill feed at higher grades from Mount Gibson in years to come. We also have a limit of how much open pit ore we can displace with higher grade underground ore through the mill before we affect what is now a very optimized open pit mine plan and contract, potentially impacting productivities and unit costs. The underground material is higher grade than the open pit and that of the Golden Range project, logically it has the tenure to be able to be trucked to another hub without affecting operations at Mount Gibson.
From our reserves base and near-term production platform of 400,000 ounces per annum, we now evaluate how best to optimize this situation and position our business to go to the next level. With that in mind, we're in the final stages of completing the first leg of the Range journey. We have built a 2.5 million tonnes per annum plant quietly and are now commissioning this project while concurrently meeting last year's production guidance. Taking Karlawinda to a nameplate capacity of 6.5 million tonnes per annum and underpinning a low-cost, 10-year, 150,000 ounce per annum project in the coming quarters. I'll hand you back to Shane now.
Thanks, Paul. As noted, the Range 500 aspiration contemplates a steady state Mount Gibson with a surplus of high-grade underground material. Coupled with the exciting Golden Range opportunities, we believe there is justification to explore a second processing hub to optimize this position and maximize the value of the full region. Range 500 sets out our aspiration to reach 500,000 ounces per annum within five years. This represents a sensible step up from an already near-term plus 400,000 ounce per annum production profile that is firmly underpinned by reliable reserves and well-planned project execution. Over the past five years, Capricorn has operated Karlawinda at an industry-leading cost base while preserving a 10-year mine life, now at an elevated production rate of 150,000 ounces per annum going forward.
During the same period, the Mount Gibson Gold Project has grown materially year after year into the substantial production profile defined in the PFS. The aspiration outlined here is the final layer of upside still to be fully defined, yet one in which we hold strong confidence. At the macro scale, we believe the Yalgoo-Singleton Belt retains significant potential for further large untapped endowments. The idea that Mount Gibson could remain the only major deposit of its type in the region strikes us as unlikely. Guided by that view, we pursued a deliberate consolidation strategy. We now control more than 4,500 sq km across the belt, capped by the strategically important Warriedar acquisition completed last year. The combination of existing roads, water licenses, and distribution networks from previously permitted operations at Golden Range has given Capricorn genuine belt-scale optionality.
Importantly, the high-grade endowment we expect to bring to bear at Mount Gibson, together with Warriedar's existing 1.4 million ounces of inventory, provides a solid baseload for the project. While we will always aim for major discoveries, even modest finds can now become incrementally accretive over time. With the Mount Gibson Gold Project's mine life now extending towards two decades and beyond, we see this cap-scale tenure package as a key pillar of our medium-term growth plans. I'll hand back to Paul.
The early-stage concept that we are contemplating for a second processing center is something likely similar to what we are currently commissioning at Karlawinda. A 1.5 to 2.5 million tonnes per annum processing hub, treating the 1.4 million ounce Golden Range open pit resources along with surplus high-grade underground material trucked north to this facility from Mount Gibson. This is imminently permittable and buildable given there is an existing permitted plant and tailings facility with no identified federal permitting issues, given its permitted status and being subject to an active mine development and closure plan. Given that we are close to completing something similar at Karlawinda for a forecast AUD 140 million of capital, we believe that this is not a complicated undertaking to be pursued aggressively.
We will achieve this through extensive drilling programs currently being executed both at Golden Range and Mount Gibson to deliver on the inventories that we clearly have great conviction on. These will support a study detailing this concept in H1 FY27 before an FID on the project be made in calendar year 2027. Mark.
Thanks, Paul and Shane, for that comprehensive presentation update. Just to recap before we open the line for questions. The Karlawinda expansion is on track for commissioning later this quarter, and the project is guided to have a long-term production rate in the order of 150,000 ounces per annum. The Mount Gibson PFS shows the quality of the project that we continue to expose there, particularly with the underground reserves now coming into the mine plan and taking the production rate to 260,000 ounces per annum. It's worth reflecting on the huge value to the project that the last two years of drilling on the underground targets has delivered.
Noting that a lot of this work would not have been contemplated for a number of years post-startup had it not been for the time we had available to us whilst we were progressing federal permitting for the project. I don't think there's any doubt that we've delivered a company making body of work today that's born out of turning frustration into opportunity, which is something internally that we're very proud of. We're in a position today where Capricorn's production outlook is 400,000 ounces per annum, which is a great position for the company to be in. The aspiration in Range 500 is to take 400,000 ounces per annum to beyond 500,000 ounces per annum in five years with a second Mount Gibson processing plant at Golden Range.
This reflects our growing confidence in the quality and scale of the underground inventory emerging at Mount Gibson and how it might also help expedite production from the resources we acquired at Golden Range last year. To this end, we're now committed to the work to evaluate the potential to optimize the broader Mount Gibson project in the medium term as we drill out the underground opportunities. We really look forward to delivering the results of those work streams over the next 12 months to fulfill that aspiration. Thanks very much for your time. That concludes the call. We'll now open the line for any questions that you might have.
Thanks, Mark. As mentioned, we will now begin the Q&A session. For those listening by phone and would like to ask a question, please press star, followed by one on your telephone keypad to raise your hand and join the queue. To withdraw your question, simply press star one again. When called upon, please use your handset, ensure your line is unmuted, and be ready to ask your question. Today, we kindly ask that you limit your questions to one and one follow-up per person. Again, that is star one to join the queue. Your first question is from the line of Adam Baker from Macquarie. Please go ahead.
Good morning, Mark, Paul, and Shane. Thanks for the update today. Might just kick off with the obvious question, on WA state approvals. Just wondering if you can give us an update on the timeline here. I note that you're finalizing the environmental review documents, so in the latter stages there. That's opening up to a public review phase. What is the timing, I guess? Is it like a three-month process from here? Or is there some upside, do you think?
Thanks, Adam. It's Paul here. Just to update with the ERD document has been finalized and submitted. We hope for that to be reviewed and available for public comment in the coming weeks. We've guided for that process to be completed in the following quarter. We're hopeful that it is concluded within that time frame. Recent precedents guide us to think that's possible.
That's great. Thank you. Just as a follow-up, just on the underground upside for the project, noting that you've only got 365,000 ounces in underground reserve. I guess what do we need to see to backfill the production profile to that 260 level, into the later years? Is it just an infill drilling story? Just noting that we don't see Lexington in there yet, are we likely to see, I guess the underground growth coming from Lexington or Orion South or potentially even both? Thank you.
Adam, Shane here. What's interesting during the trade-off study, if we had left the previous open pit design, we would have had circa nine years of underground out of this PFS. The reality is project first, that came into the 2,200 expanded reserve shell. With three-quarters of the ounces now sitting in that AUD 2,200 per ounce pit shells. That did decrease the amount of inventory we had available in the underground. Pleasingly, with that drilling, we've tagged multiple, additional loads, and it's really just an extension and infill story there, with Orion South. We have always had great ambitions to drill out underneath Lexington through to Hornet. In between there's a deposit in Enterprise. They have all the hallmarks of extending underground. Time will tell, and the drill bit will ultimately tell us the truth.
We just need the time for the MRE category uplift to bring everything up to the required density and pad out that production profile. It's at depth, so it takes a lot of meters, but we've committed the funds to it, and we'll bear it out in time.
Thank you.
Your next question comes from the line of Daniel Morgan of Barrenjoey. Please go ahead.
Hi, Mark and team. Just to follow up on that underground growth exploration piece at Mount Gibson . What is the strategy there to grow it? Do you get into, I mean, referring to slide 10, just with that map. It looks like you could potentially do an exploration decline off to Lexington, Enterprise and Hornet. Do you do that or do you drill from surface? Thank you.
It'll probably be a combination of both in time, Dan. We need to get Lexington up to the required density to get first part, to get some mining stopes into the mine plan there. Then I think we'd have the confidence to obviously push down the exploration decline to do the further work to bring it all up to the required category. Similar to Orion South, we're not going to do everything from surface, but we need to get enough confidence to be able to put the capital into that decline prior. We'll just follow our nose in exactly the same way that we've done with Orion South, and onto these new targets in Lexington, Enterprise and Hornet.
Thank you. Just a follow-up question. It strikes me that part of your plans that you've outlined today is you've got some constraints regarding your milling throughput, where if you do too much underground, it starts to displace the open pit, which creates some issues there. You formerly haven't changed your throughput numbers, it doesn't appear. Could it be that you could do potentially more on throughput? Are these throughput numbers conservative and therefore that would fix your constraint issue that you seem to be mulling? Thank you.
I think as we stated earlier, Dan, as you see in Karlawinda, we're hopeful that our normal design process bears out upside in the future. For the purpose of the PFS and the work done here, we've run with the 5 million tonnes per annum ceiling. However, the approach for the Golden Range opportunity is born out of what we see as a massive opportunity for the underground resources, as well as at Golden Range. We're going to manage that accordingly, but I think there's definitely going to be a need to look at something else outside of Mount Gibson.
Okay. Thank you, Paul, for your perspectives.
Your next question comes from the line of Matthew Frydman of MST Financial. Your line is open.
Sure. Thanks. Morning, Mark and team, and thanks for hosting the call and taking some questions. Can I ask on that third Golden Range processing hub, obviously it's still early days, but maybe you can give us a bit of a guide, firstly on CapEx conceptually. If I look at the Mount Gibson project, it's AUD 474 million, call it AUD 500 million for a 5 million tonnes per annum plant and supporting infrastructure and mine development, et cetera. Would it be unfair to, I guess, roughly scale that down for the 1.5 million-2.5 million tonnes per annum case that you're conceptually looking at? Call it AUD 250 million of CapEx. Is that ballpark the right number?
Matt, to interrupt you.
Yeah, go ahead, Mark.
I think the stronger guide would be to look at what we're just very close to finishing at Karlawinda. We've put on 2.5 million tonnes per annum of throughput. There'll be pluses and minuses given that some of the infrastructure's already in place at Karlawinda, but if you recall, that's AUD 140 million spend, and we're studying at Golden Range 1.5-2.5. I think that's probably ± a standard deviation, that's the place to start, I think.
That's very helpful. Thanks for that, Mark. I guess as a follow-up, similarly on all-in sustaining cost, obviously you have to factor in some trucking there, but is there any sort of aspiration when you look across your portfolio and the other hubs? Would you be aiming that all-in sustaining cost for a third hub is circa or below AUD 2,000 an ounce or something like that, or is it too early to put a number on that?
I think it's too early, bear in mind that the material at Golden Range is going to be sitting right at the mill head, so that's helpful. The higher grade material that we intend to truck up the road will carry some additional costs. I would hope that we'd still be targeting something in the realm of the broader cost for Mount Gibson . Yeah, like you say, there's still water to go under the bridge to do that study work. We're certainly not thinking that it's something that's going to have a material differential to what we're currently planning at Mount Gibson itself.
That's helpful. Thanks, Mark. I'll queue up for some more questions. Cheers.
Your next question comes from the line of Hugo Nicolaci of Goldman Sachs. Please go ahead.
Morning, Mark, Paul, Shane, Will. Congrats on the outlook. Obviously, a lot of work has gone into the comprehensive review here. Firstly, just at Karlawinda. Obviously, as that project completes your 150,000 ounce a year target, can you just remind us what throughput that assumes and what you can push the plant to in terms of throughput on softer material? Then maybe just when in the mine plan you might have more of that softer material available?
Look, I'll split it up for you, Hugo. The throughput capacity for the expanded plant is 6.5 million tonnes per annum. There isn't a huge amount of softer material for the balance of the mine plan. Generally speaking, that is meted out across the production profile.
I think in general, Hugo, 150,000 ounces per annum is a good target for Karlawinda, and was one that was contemplated for the expansion, which underpins the reserve update today. You would have seen that we've sold for a higher gold price. That brings down the head grade. All that was contemplated when we made the decision for the expansion. I think it's just a very low risk, 150,000 ounces per annum, and for 10 years and beyond.
Got it. That's helpful. Just turning to Mount Gibson, I think from memory, you've got MACA lined up for the open pit, but can you just walk us through where you're at in terms of plant and infrastructure with a contractor and maybe the confidence in terms of getting, contractor and then labor availability, just given the pipeline of projects we're seeing in W.A. at the moment?
I'll speak to the plant stuff initially. We've awarded to Interquip, which is the company currently building our Karlawinda expansion, which is coming in on time and on budget. Our confidence in terms of delivering that project, is high. I want to be clear that that full project is designed, defined, and every bit of equipment is sitting in a procurement package ready to go. We feel we've got a good handle on that. Just to clarify, too, all of the contracts, be it Interquip or any of the other infrastructure projects, are subject to conditions precedent around permitting.
Got it. That's helpful. I'll return the queue.
Just a note, if you would like to join the queue and ask a question, please press star one. Your next question comes from the line of David Coates of Bell Potter Securities. Please go ahead.
Morning, Mark, Shane, and Paul. Congratulations. Big update out this morning. Quick questions from me. A couple have already been answered, but I guess sort of looking at Golden Range, you touched on the permitting advantage or some of the permitting sort of head starts it has got. If you could just run us through a couple of those in a bit more detail.
I think, Dave, look, again, we have got to finalize the work on doing the studies and work out exactly what it is that we are going to build. I think the fact that there is a permitted processing facility and a permitted tailings dam means that the permitting exercise will be the normal variation that we perform every year at Karlawinda, be it a tails dam lift or a waste farm extension. It is a very straightforward process, one that we do every year and is very well understood. We have not completed all of that work yet, but it is a path we take quite frequently. We think that is pretty straightforward given that what we do build will not be conceptually dissimilar to what is there now, albeit a little more robust and larger.
Okay, cool. Again, just obviously you guys have been looking at the optimization of a second process plant up there. I imagine there is some, I guess, sort of more qualitative kind of factors that are sort of supporting that decision around potential resources and resource growth. If you can just give us a bit of run through how you are seeing that potential at the moment and how that is kind of feeding into, I guess, or supporting a second milling operation up there.
Yeah. Dave, Shane here. Obviously, it has taken a bit of time for us to fully digest the Golden Range resource base, and there will be an update to some of the drilling, and results in this quarterly. Conceptually, we purchased Warriedar on the back of both, obviously, the processing plant permits and the like, and that inventory, and we saw a free milling inventory there that we liked the look of. We will continue to drill that out and bring it to bear. Conceptually, we always thought that it was at a probably subscale for our typical project ambitions, which is when the underground for Mount Gibson obviously started to make the acquisition make a lot more sense to be able to get it to the third leg of the stool that we are expecting.
I think just watch this space, we are dedicating budget to proving out that inventory.
Just one other point there, Dave, I did make it in the presentation, just to reiterate it. Remember, the grade differential between Golden Range open pit and Mount Gibson open pit is minimal. We know that the open pit at Mount Gibson's already sitting at circa two decades. The question is, if we truck that material south to Mount Gibson, when are we going to do that? There's not going to be any incentive to do that for a very long time. That then sort of by reverse almost implies that there's no value in those resources, where the truth is actually the opposite of that.
We've got 1.4 million ounces of resources there, some of which is going to be really economic and really profitable, we're not going to get the chance to bring it into the mine plan if we don't do something at Golden Range itself. Really what you're talking about is the delta in cost between doing some sort of expansion at Mount Gibson with all the permitting and footprint change and everything that comes with that, versus if we've got enough underground inventory surplus to annual requirements from Mount Gibson, that's higher grade, it's more imminently trackable. We truck that north, we bring those resources that are going to have zero NPV if we're mining them in 20 years. We bring those resources into play in the next five years. That's kind of the broad thinking.
As Shane said, it's sort of underpinned by our confidence in having enough underground material to put into the Mount Gibson plant take up any sort of organic throughput upside there a surplus volume that can go up the road to underpin an economic operation at Golden Range, bringing into play those open pit resources that are there, at the same grade as Mount Gibson.
Yeah. No, I think it makes a lot of sense, also, I guess it provides that strategic optionality of being able to monetize a bigger part of your footprint with that processing facility up there as well.
Absolutely. As Shane always says, there hasn't been a lot of exploration on a lot of the tenure further to the north. You would hope that once you put a, whatever it might be, a 1.5 million-2.5 million tonnes per annum processing plant in that area, it hopefully, from an exploration perspective, it just lights up all those opportunities because they no longer have to truck 100 or 80 kilometers to the south to Mount Gibson, and they no longer have to compete with the background ore that's been mined out of the open pit at Mount Gibson that's already under a contract that we can't disrupt. That's the hope, that not only does it become an economic hub in its own right, but it opens up that whole northern part of the tenure for good exploration and hopefully discovery.
Yep. No, excellent. Thanks so much, guys.
Your next question is from the line of Ben Lyons of Jarden. Please go ahead.
Thank you. Good day, Mark, Shane, and Paul. Thanks for the great update. Just looking at the OpEx breakdown, and noting that the underground mining cost appears conservative enough given the shallow depths and very consistent geometry that you alluded to in your introductory remarks. Also great to see that industry-leading processing cost of AUD 15 per tonne. I guess my question is that, I assume this is pretty well informed by your real-life experience at Karlawinda, and that's obviously a key reason why you continue to be a sub-AUD 2,000 all-in sustaining cost gold producer.
Absolutely, Ben. It's informed by obviously. The flow sheets aren't dissimilar, so we've got a great deal of confidence out of that. There's been some small changes between the two. There's some reagent adjustments between the two projects. We don't use lead nitrate, so that's a significant cost that we removed from Karlawinda. Equally, we've got really good and recent test work for all of those deposits informing the Mount Gibson mine plan. We think we're coming off a pretty good position and understand those costs well.
Awesome. Thanks, Paul.
I'm grumpy that they're not still AUD 11 a tonne, Ben.
Some things, yeah.
You're going to get pretty grumpy about the follow-up question, Mark, which is, I'm sure it's in the documentation somewhere, but obviously, again, circling back to one of the earlier questions on the call, it looks like a material part of the upside for the Mount Gibson Gold Project remains the backfill opportunity for those underground ounces, which we assume will come with the investment in the drill bit. The question just is, what's the indicative amount that you'll be spending on exploration, going forward? Again, I acknowledge that's probably going to be informed by your success with the drill bit. Yeah, if you can just sort of outline the exploration expenditure going forward, please. Thanks.
For the coming financial year, we're deploying AUD 50 odd million of exploration. Split is AUD 40 between Mount Gibson and AUD 10 to Karlawinda for the next 12 months, Ben, that is heavily weighted towards the underground opportunities. That's both extending Orion South and bringing Lexington into that mine plan. Yeah, the run rate in which we've delineated and expanded Orion South underground in the last 18 months, we plan to turn our focus to Lexington. I will note, too, that as we know, the geometry of Orion South in particular is particularly torquey in this space at 100,000 ounces per level. It's not overly brave step-out drilling to expand upon that inventory quite dramatically.
I'd like to think we can maintain the current cadence of bringing those underground resources to bear and push that production run rate out to the right.
It's true resource definition drilling, too. There's a lot of big budgets out there in the space, a lot of that's with grade control on a one or two year near-term production horizon. We have 19 years here, obviously we're looking at backfilling those year sevens and beyond. This is torquey expenditure.
Yep. Thanks, Shane and Paul. Sorry, rather than rejoin the queue, I'll squeeze a third one in. Just on the other hidden value that's in the portfolio, the antimony opportunity with the Golden Range projects as well. Just wondering if that's sort of on your schedule at this point in time. Maybe just spend a little bit on studies and possibly bolting on an antimony circuit at the back end of the processing plant. Thanks, guys.
Yes. Certainly, I think, Ben, in the long term, a lot of Golden Range's value will be born out of the sulfides project, which obviously, if you make that step, you're silly to not explore the antimony upside. Of course, with that, you need to take positions on the market and the like, particularly the bifurcation of that between China and the rest of the world. We're doing a lot of work in that space now with parties that understand that a lot better than we do. We've obviously come up to the curve in a very short period of time.
Those, we're currently doing test work programs. We're pulling the core for those historic sulfide resources. That test work will be done in the next while. As Shane says, we will overlay that against market and what's the right flow sheet. In answer to your question, we will size and scope the sort of stage 1 free milling opportunity with this in mind.
Thank you very much. Thanks, Paul. Thanks, Shane. Thanks, Mark.